关于Overhauser!

When A.W. Overhauser was a graduate student at Berekely in the 1950's, he predicted that if one saturated the conduction electron spin resonance in a metal, the nuclear spins would be polarized 1000-fold more strongly than their normal polarization in the absence of the saturation (1,2). This means that the population difference for the nuclear spin has increased 1000-fold without the need to increase the magnetic field, locally or externally. It has, in effect, obtained the electron spin Boltzmann factor. It is easy to see why the magnetic resonance community greeted this prediction with great skepticism. In fact, it was widely believed for a short period of time that this prediction had to be in violation of the second law of thermodynamics, ie. the system ran uphill. However, Overhauser was correct. The experiment was successfully performed by Carver and Slichter (3,4) using Li metal, a description of which may be found in Slichter's text.

1. A.W. Overhauser, Phys. Rev. 91, 476 (1953).
2. A.W. Overhauser, Phys. Rev. 92, 411 (1953).
3. T.R. Carver and C.P. Slichter, Phys. Rev. 92, 211 (1953).
4. T.R. Carver and C.P. Slichter, Phys. Rev. 102, 975 (1956).